import pandas as pd
import matplotlib.pyplot as plt

dict = {"x": [0, 1, 2, 3, 4, 5, 6], "y": [900, 400, 200, 300, 500, 600, 800], "z": [600, 100, 50, 80, 200, 250, 700]}
plt.rcParams['font.sans-serif'] = ['SimHei']
df = pd.DataFrame(dict)
